i'm actually using the same method of laser ranging on my current robot project except i'm using one of those DIY laser level things that draw a straight line of laser light so i don't need the servo.it works pretty well but you need a fair bit of processing power on board.

Hey folks! Here's a little something I built about a month ago, but couldn't get enough time from college to write about it. Well, it's an object tracking camera panner which tracks any object moving in close range. Unlike my previous method for object tracking, this technique will track almost any moving object, irrespective of its color, using two lasers for edge detection. Depending on which laser is focused on the object, the computer decides which direction to drive. I came up with this idea after watching a video on SoR (Society of Robots) of a sumo robot, called Stampy. Stampy uses a single IR rangefinder for edge detection. Watch the video below:

I used lasers instead of IR rangefinders. My initial plan was to use a single laser..but then it occurred to me that I would have to shake the laser left/right continuously for tracking the trailing edge of an object. So, I decided to go with two lasers instead of one.